Dual-Chambered Passenger Airbag

ABSTRACT

An airbag includes an outer shell defining an interior, at least one vent opening structured to enable fluid communication between the interior and an exterior of the airbag, and a divider dividing the airbag interior into an upper chamber and a lower chamber. The divider is deflectable in a first direction toward the lower chamber and in a second direction toward the upper chamber. A vent cover is coupled to the at least one vent opening and to the divider so as to close over and restrict a flow of gas through the at least one vent opening when the divider is deflected in the first direction, and so as to permit the vent cover to open so as to enable an unobstructed flow of gas through the at least one vent opening when the divider is deflected in the second direction.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of co-pending andco-owned U.S. application Ser. No. 14/502,232 having a filing date ofSep. 30, 2014, which claims the benefit of U.S. Provisional ApplicationSer. No. 61/884,944, filed on Sep. 30, 2013, the disclosures of whichare herein incorporated by reference in their entirety.

BACKGROUND OF THE INVENTION

The present invention relates a passenger airbag, which is filled withgas during an emergency situation such as, for example, a frontal orside impact.

SUMMARY OF THE INVENTION

In one aspect of the embodiments described herein, an airbag is providedincluding an outer shell defining an interior, at least one vent openingstructured to enable fluid communication between the interior and anexterior of the airbag, and a divider dividing the airbag interior intoan upper chamber and a lower chamber. The divider is deflectable in afirst direction toward the lower chamber and in a second directiontoward the upper chamber. A vent cover is coupled to the at least onevent opening and to the divider so as to close over and restrict a flowof gas through the at least one vent opening when the divider isdeflected in the first direction, and so as to permit the vent cover toopen so as to enable an unobstructed flow of gas through the at leastone vent opening when the divider is deflected in the second direction.

In another aspect of the embodiments of the described herein, an airbagis provided including an outer shell defining an interior, and at leastone vent opening structured to enable fluid communication between theinterior and an exterior of the airbag. A divider divides the airbaginterior into a first chamber and a second chamber separate from, and influid communication with, the first chamber. The divider is structuredto deflect toward the second chamber when a pressure in the firstchamber is greater than a pressure in the second chamber, and is alsostructured to deflect toward the first chamber when a pressure in thesecond chamber is greater than a pressure in the first chamber. A ventcover is closable over the at least one vent opening so as to restrict aflow of gas through the at least one vent opening. The vent cover isalso openable so as to permit an unobstructed flow of gas through the atleast one vent opening. An inter-chamber venting system is operativelycoupled to the divider. The venting system is openable to permit gas toflow unobstructed from the first chamber through the divider into thesecond chamber, when a pressure in the first chamber is greater than apressure in the second chamber. The venting system is closable torestrict gas backflow from the second chamber into the first chamberwhen the pressure in the second chamber is greater than a pressure inthe first chamber. A tether operatively connects the vent cover to thedivider such that the vent cover is closed when the divider is deflectedtoward the second chamber, and such that the vent cover is open when thedivider is deflected toward the first chamber.

In another aspect of the embodiments described herein, an airbag isprovided including an outer shell defining an interior and a dividerdividing the interior into an upper chamber and a lower chamber separatefrom, and in fluid communication with, the upper chamber. The divider isdeflectable toward the lower chamber and also toward the upper chamber.At least one vent opening is structured to enable fluid communicationbetween the interior and an exterior of the airbag. A vent cover isclosable to restrict a flow of gas through the at least one vent openingwhen the divider is deflected in the first direction, and openable so asto permit an unobstructed flow of gas through the at least one ventopening. The vent cover is operatively coupled to the divider such thatthe vent cover is openable when the divider is deflected in a directiontoward the first chamber and closed when the divider is deflected towardthe second chamber. The divider is structured to deflect in a directiontoward the first chamber responsive to pressure exerted on the airbagexterior by contact with a torso of a vehicle occupant, prior to contactbetween a head of the occupant and the airbag.

In another aspect of the embodiments described herein, an airbagincludes at least one panel defining an interior of the airbag, at leastone vent opening structured to enable fluid communication between theinterior and an exterior of the airbag, and a divider positioned in theinterior so as to divide the interior into an upper chamber and a lowerchamber. The divider has least one opening formed therealong. The atleast one opening is positioned such that all edges of the at least oneopening reside within a zone (Z3) bounded by a first vertical plane(P15) residing a predetermined distance (1000 f) from an inflator side(22) of the airbag toward an occupant contact side of the airbag, and asecond vertical plane (P14) passing through a predetermined location(701) defined through a shoulder bolt (701) of a Hybrid III 6-year oldanthropomorphic test device in Position 1 defined by FMVSS208 Out ofPosition testing. The divider is deflectable in a first direction towardthe lower chamber and in a second direction toward the upper chamber. Avent cover is operatively coupled to the at least one vent opening andto the divider so as to close over and restrict a flow of gas throughthe at least one vent opening when the divider is deflected in the firstdirection, and so as to permit the vent cover to open so as to enable anunobstructed flow of gas through the at least one vent opening when thedivider is deflected in the second direction.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a passenger-side airbag (in an inflatedstate) incorporating an airbag venting system in accordance with anembodiment described herein.

FIG. 2A is a schematic view of the airbag embodiment shown in FIG. 1from the perspective of a vehicle occupant, and showing the airbagduring an initial portion of the airbag deployment with vent covers in aclosed condition.

FIG. 2B is a schematic view of the airbag embodiment shown in FIG. 1from the perspective of a vehicle occupant, and showing the airbagduring a final portion of the airbag deployment with vent covers in anopen condition.

FIG. 2C is a schematic perspective view of the airbag embodiment shownin FIG. 2B.

FIG. 3 is an exploded perspective view of a portion of an airbag dividerand an associated vent hole lid member attached thereto by a tethermember, in accordance with an embodiment described herein.

FIG. 3A is a cross-sectional view of a patch member, vent hole lidmember and tether member as shown in FIG. 3 attached to an airbag panel,in accordance with an embodiment described herein.

FIG. 4 is a schematic perspective view of the airbag embodiment shown inFIG. 2A.

FIG. 5 is a schematic view of the airbag embodiment shown in FIG. 1 fromthe perspective of a vehicle occupant, and showing the airbag during anintermediate portion of the airbag deployment.

FIG. 6A is a schematic view showing relative proportions ofAnthropomorphic Test Devices and relevant parameters used to define thedesired positioning of the divider within the airbag, in accordance withembodiments of the present invention.

FIG. 6B is a side view of an airbag in accordance with an embodimentdescribed herein mounted and deployed in a vehicle in front of a seatedpassenger.

FIG. 7 is a schematic side view of an airbag in accordance with anotherembodiment described herein.

FIG. 8A is a schematic side view of a portion of the airbag shown inFIG. 7 in the initial stages of inflation, showing locations of theinter-chamber venting opening(s).

FIG. 8B is a schematic side view of the airbag of FIGS. 7 and 8A showinga later stage of inflation of the airbag.

FIG. 9A is a schematic side view of a 3 year-old Anthropomorphic TestDevice in Position-1 for Out of Position testing under FMVSS StandardNo. 208, prior to activation of a vehicle airbag.

FIG. 9B is a side view of FIG. 9A after activation of a vehicle airbagillustrating an undesired location of a divider opening and associatedvalve mechanism at a point rearward from the occupant or proximate theinflator.

FIG. 9C is a side view of FIG. 9A after activation of a vehicle airbag.

FIG. 9D is another side view of FIG. 9A after activation of a vehicleairbag illustrating the determination of zone 3 (Z3), and a desiredlocation of the divider openings and associated valve mechanisms.

FIG. 10 is a schematic representation of an exemplary vehicle occupantprotection system including an airbag in accordance with an embodimentdescribed herein.

DETAILED DESCRIPTION

Embodiments of the present invention will be described below withreference to the drawings. One of ordinary skill in the art willappreciate the various aspects of airbag design, construction andoperation applicable to the embodiments of the present inventiondescribed herein. U.S. Pat. Nos. 6,886,857, 7,857,347, 8,128,124, and8,322,748, for example, describe many such aspects and are incorporatedherein by reference in their entirety, but not by way of limitation.

FIG. 1 is a perspective view of one embodiment of a passenger-sideairbag 10 (in an inflated state). The airbag embodiment shown in FIG. 1is formed from three panels. Specifically, the airbag is formed of amain panel 12, a right side (when viewing the airbag from a seatedposition) panel 16, and a left side panel 14 opposite the right sidepanel 16. Each of the side panels 14, 16 is generally planar (when theairbag 10 is not inflated). The main panel 12 connects the left andright side panels and wraps around the airbag 10. As a result, theentirety of the left edge of the main panel 12 is connected along a seam70 (e.g., by stitching, sewing, adhesive attachment or other suitablemeans) to the left panel 14 and the entirety of the right edge of themain panel 12 is connected along a seam 72 (e.g., by stitching, sewing,or other suitable means) to the right panel 16. In the embodiment shown,the panels 12, 14 and 16 combine to form an outer shell of the airbag.

The main panel 12 has both a front impact side or occupant contact face20 and a rear inflation side 22. Side panels 14 and 16 and main panel 12also combine to define a mouth 22 a of the airbag through which gas isinjected into the airbag. After wrapping around the airbag 10, ends ofthe main panel 12 are joined at the rear inflation side to defineopposite edges of mouth 22 a. In addition, the rear inflation side 22has slits (not shown) which are sized to receive an inflator (notshown), and may also include holes (not shown) which are sized toreceive bolts (or other suitable fasteners) that are configured tosecure the airbag 10 to the body of an automobile or other device.Portions of one or more of panels 12, 14, 16 defining an upper chamber102 of the airbag may also incorporate one or more vents (such as, forexample, holes 210 and 212 in the embodiment shown in FIG. 1) therein torelease gas from the upper chamber in a controlled manner during contactbetween a passenger and the airbag. Panels 12, 14 and 16 and divider 100may be formed in a known manner from gas-impermeable fabric(s) or othersuitable gas-impermeable material(s).

A first vent hole (shown schematically as element 210) is provided inleft panel 14, and a second vent hole (shown schematically as element212) is provided in right panel 16. Vent holes 210 and 212 enable fluidcommunication between the interior of the airbag and the exterior of theairbag. In the embodiment shown, the vent holes 210 and 212 enable fluidcommunication between the upper chamber 102 and the exterior of theairbag.

Referring to FIGS. 2A, 2B, 3 and 3A, a pair of actuatable vent covers orlid members 60 a and 60 b are attached to associated exterior surfacesof the airbag so as to enable each lid member to cover an associated oneof vent holes 210 and 212. In a closed condition, each lid membercontacts the bag exterior to close its associated vent hole therebyrestricting gas flow from the airbag interior through the vent hole tothe exterior of the airbag. When a lid member is in an open condition,the portion of the lid member covering the vent opening is spaced apartfrom the side panel to which it is attached and spaced apart from all ofthe edges of the vent opening, thereby removing obstructions blockingthe vent hole itself and permitting gases to flow from the airbaginterior out of the airbag through the associated vent hole.

Referring to FIGS. 1 and 4, a divider 100 is stitched or otherwisesuitably attached along a perimeter thereof to interior surfaces of themain, left and right airbag panels. The divider 100 is attached to thepanel interior surfaces so as to form a gas-tight seal between thedivider and the panels to which it is attached. Divider 100 divides theairbag interior into a first or upper chamber 102 and a second or lowerchamber 104. At least one opening 112 a is provided to enable fluidcommunication between upper chamber 102 and lower chamber 104.

An inter-chamber venting system is provided to permit gas to flow from afirst one of chambers 102 and 104 into the other one of the chambers 102and 104, and also to restrict backflow from the lower chamber 104 backinto the upper chamber 102. In one embodiment, a flow restriction valvemechanism (schematically shown as element 113 in FIGS. 1 and 4) isincorporated into or operatively attached to divider 100 for restrictinggas flow through opening 112 a between the two chambers. The valve mayhave any of a number of structures suitable for restricting gas flow inthe airbag interior, in the manner described herein.

In the particular embodiment shown in the drawings, the flow restrictionvalve mechanism is positioned and structured to permit gas flowing intoor residing in upper chamber 102 to flow freely into lower chamber 104,while restricting backflow of the gases from the lower chamber into theupper chamber. The gas flow rate from the upper chamber 102 into thelower chamber 104 through opening 112 a may be controlled by controllingthe dimensions of opening 112 a and the valve structure and dimensions.Further to this end, in particular embodiments, the valve is structuredto close responsive to occurrence of a pressure differential between thelower and upper chambers tending to force gas in a direction oppositethe airbag fill direction (i.e., tending to force gas in a directionfrom the second chamber into the first chamber), thus enablingmaintenance of a prolonged sustained relatively high, inflated pressurein the lower chamber.

In the embodiment shown in the drawings, opening 112 a and theassociated valve mechanism 113 restricting flow through the valve arelocated proximate a center of the divider, or at least spaced apart fromthe panels forming the walls of the airbag. In alternative embodiments,the divider opening(s) and associated valve mechanism(s) may bepositioned along a seam or intersection between the divider 100 and oneor more of the airbag panels 12, 14 and 16. Examples of dividers andvalve structures suitable for controlling gas flow between the upper andlower chambers in accordance with the applications contemplated hereinare disclosed in U.S. Provisional Application Nos. 61/865,095 and61/862,491, the disclosures of which are incorporated herein in theirentireties. Other divider and/or valve configurations may also be used.However, it is desirable that any valve mechanism used rapidly actuate(responsive to a relatively higher pressure in the lower chamber) toprevent or restrict backflow of gases into upper chamber 102, such thatpressure in the lower chamber and the resulting support for the torso ofthe vehicle occupant are maintained for a time period sufficient topermit venting of the upper chamber gases responsive to pressure exertedby the occupant's head on the airbag exterior of the upper chamber.

In embodiments described herein, the divider is structured and attachedto the panels 12, 14 and 16 such that the portions of divider 100 spacedapart from the attachments or not directly attached to the outer panelswill deflect in a first direction “A” (as shown in FIG. 2A) toward lowerchamber 104 responsive to a pressure differential inside the airbagwherein the upper chamber pressure is greater than the lower chamberpressure (for example, during the initial fill stage after airbagactivation). Divider 100 is also configured and attached to panels 12,14 and 16 such that the portions of divider 100 spaced apart from theattachments or not directly attached to the outer panels will deflect ina second direction “B” (as shown in FIG. 2B) extending toward upperchamber 102 responsive to a pressure differential inside the airbagwherein the lower chamber pressure is greater than the upper chamberpressure (for example, when a passenger impacts a lower portion of theairbag, causing a pressure surge in lower chamber 104). The divider maybe generally planar or deflect slightly downwardly due to gravity whenthe pressures in the upper and lower chambers are effectively equal.

In addition, divider 100 is configured and attached to panels 12, 14 and16, and tether members 70 a and 70 b (described in greater detail below)are structured and attached to associated portions of the divider atanchor locations 70 a 1 and 70 b 1 specified such that during deflectionor bulging of the divider in direction “A” into configuration 900 ofFIG. 2A, tension is maintained in tethers 70 a and 70 b by thedeflection of the divider, whereby lid members 60 a and 60 b aremaintained in a closed condition against the pressure exerted by gasesinside the airbag, thereby preventing pressurized gases from exiting theairbag through openings 210 and 212. Also, divider 100 is configured andattached to panels 12, 14 and 16, and tether members 70 a and 70 b arestructured and attached to associated portions of the divider atlocations 70 a 1 and 70 b 1 specified such that during deflection orbulging of the divider in direction “B” (opposite direction “A”) intoconfiguration 902, the resulting travel of anchor locations 70 a 1 and70 b 1 in direction “B” permits the pressure inside the airbag to openlid members 60 a and 60 b, there by permitting gases to escape throughopenings 210 and 212.

Referring to FIGS. 3 and 3A, in one particular embodiment of the lidmembers 60 a and 60 b and their associated attachment structures, thelid members include or are connected to associated patch members 61 aand 61 b, each formed of an annular woven, gas-impermeable cloth orother suitable material and attached to the peripheral edge ofassociated ones of each of openings 210 and 212 from the outside of theairbag 10. Reference numeral 62 a (FIG. 3) designates an associated seamstitching the patch member 61 a to left panel 14. A similar seam 62 b(not shown in FIGS. 3 and 3A stitches the patch member to right panel16. Each of seams 62 a and 62 b extends into annular shapes along theouter periphery of its respective patch member.

Attachment of the patch member 61 a and operation of the associated lidmember 60 a on left panel 14 will be described in the followingparagraphs. However, it is understood that attachment of the patchmember 61 b and operation of the associated lid member 60 b on rightpanel 16 is the same as for patch member 61 a and lid member 60 a.

The vent holes, lid members and associated structures used in theembodiments described herein for controlling gas flow out of the airbagthrough the vents, are configured according to one of the embodimentsdescribed in U.S. Pat. No. 7,607,690, which is incorporated herein byreference in its entirety. However, other configurations of vent holes,lid members and associated structures are also contemplated.

As shown in FIG. 3, a pair of side edge portions 60 y and 60 z of theperiphery of the lid member 60 a extends from the outer peripheral edgeof the patch member 61 a. The pair of side edge portions 60 y and 60 zis connected to the left panel 14 via the seams 63 a. The respectiveseams 63 a are joined to the seam 62 a stitching the patch member 61 ato left panel 14. The side edge portion 60 a-1 on the distal end side ofthe lid member 60 a is not connected to the left panel 14. The vent hole210 is positioned between the seams 63 a.

FIG. 3 shows an axis C2 bisecting patch member 61 a and a cross-section3A-3A taken through the patch member and perpendicular to axis C2.Referring to FIGS. 3 and 3A, in the embodiment shown, a distance Dbetween a stitch position of one of the side edge portions 60 y and 60 zof the patch member 61 a on one side of axis C2 and a stitch position ofthe other one of side edge portions 60 y and 60 z on an opposite side ofaxis C2, in a state in which the left panel 14 is extended flatly, isless than a distance W between the positions of the stitches on thepatch member along the cross-section, when the patch member 61 a isextended flatly. Therefore, even when the left panel 14 is extendedflatly as shown in FIG. 3A, the patch member 61 a still remains in thesagged configuration shown in the drawing. Thus, when the patch member61 a is not pulled toward the inside of the airbag 10 by the tethermember 70 a, a space S is formed between the patch member 61 a and theleft panel 14. However, the configuration of the patch member 61 a andthe connecting structure with respect to the left panel 14 is notlimited thereto. For example, the lid member 60 a may be providedseparately from the patch member 61 a.

A tether member 70 a is provided for connecting the lid member 60 a tothe divider 100. A similarly configured and operating tether member 70 bis provided for connecting the lid member 60 b to the divider 100.

A first end of the tether 70 a is stitched or otherwise suitablyattached to divider 100 at location 70 a 1. A second end of the tether70 a passes through the vent hole 210 and is stitched or otherwisesuitably attached at a location 70 a 2 to a surface of the lid member 60a opposing the vent hole 210. Also, a first end of the tether 70 b isstitched or otherwise suitably attached to divider 100 at location 70 b1. A second end of the tether 70 b passes through the vent hole 212 andis stitched or otherwise suitably attached to a surface of the lidmember 60 b at a location 70 b 2 opposing the vent hole 212.

As previously described, tethers 70 a and 70 b are structured andattached by their ends at respective locations 70 a 1 and 70 b 1 on thedivider 100 and on their respective lid members 60 a and 60 b such thatthe lid members are in a closed condition when the divider is deflectedin direction “A” into condition 900 (as shown in FIG. 2A) and the lidmembers are in an open condition when the divider is deflected indirection “B” into condition 902 (as shown in FIG. 2B).

Referring to FIGS. 2A and 4, in a first operational phase of the airbag,upon collision of a vehicle in which the airbag 10 is installed, apressurized fluid source (not shown) is activated to inject gas in theairbag 10. During the first phase of airbag deployment, pressurized gasenters and fills upper chamber 102. The pressure within the upperchamber 102 increases such that pressure in upper chamber 102 is greaterthan pressure in lower chamber 104, which causes the divider to deflectdownwards toward the lower chamber 104. In addition, gases flow from theupper chamber 102 through the valve mechanism 113 and opening 112 a intolower chamber 104. Because the valve mechanism is structured to permitgases to flow freely from the upper chamber to the lower chamber, thelower chamber 104 rapidly fills with gases received from the upperchamber. During this phase, the vent covers 60 a and 60 b are heldclosed by tether members 70 a and 70 b attached to divider 100. Thedeflection of the divider maintains tension in the tether members, whichmaintains the closure of the vent covers 60 a and 60 b.

Referring to FIGS. 2A, 2B, and 2C, in the embodiments of the divider 100described herein, it is seen that the distance F moved by a givenportion of the divider when the divider moves from deflecting into thelower chamber 104 to deflecting into the upper chamber 102, is generallydependent upon the distance D1 along the divider of the given portion ofthe divider from a portion of the divider which achieves maximumdeflection in either of directions A and B (shown in FIGS. 2A and 2B)when the divider is fully deflected during the first or thirdoperational phases of the airbag, as described herein. This portion ofthe divider is referred to herein as the region C of maximum deflectionof the divider 100, and may be determined analytically or experimentallyfor a given airbag. In general, the region of maximum deflection willdepend on such factors as the divider configuration and the positionsand configurations of the seams attaching the divider to the panels 12,14 and 16 (and/or to any other panels to which the divider is attached.In the embodiment shown, the region of maximum deflection C willdisplace or move a greater distance than any other portion of thedivider when the deflection direction shifts from a direction toward thelower chamber to a direction toward the upper chamber. Consequently, afirst portion P1 of the divider (FIG. 2B) relatively closer to theregion C will displace a relatively larger distance F1, while a secondportion P2 of the divider that is located relatively farther from theregion C will displace a relatively smaller distance F2. In theembodiment shown, the divider 100 is structured and attached to theairbag outer panels 12, 14 and 16 such that region C lies along a planeM bisecting the airbag and divider. The location and extent of theregion of maximum deflection C may be determined analytically oriteratively, through experimentation for a given divider and dividerattachment configuration, using known methods.

In the embodiments shown in FIGS. 2A-2C, the flowrate of gases throughthe vent openings 210 and 212 may be controlled by controlling thedistances of the lid members 60 a and 60 b from their corresponding ventholes 210 and 212. For example, as seen from FIG. 3A, as the distance ofa lid member (or a portion of a lid member) from the opening increases,the area of a region Y (indicated by the dashed line in FIG. 3A) boundedby the outer edge of the lid member and the portion of the airbag panel14 surrounding the vent hole 210 correspondingly increases. This allowsa relatively larger flowrate of gases from the airbag interior throughthe vent hole 210 and into the area Y.

In a particular embodiment, the differing displacements of the differentportions of the divider during the airbag internal pressure shifts maybe used to control the amounts by which the vents are opened, byattaching the tethers to suitable locations along the divider. That is,if one or more of tethers 70 a and 70 b are attached to the divider 100relatively closer to the region C, the attachment point(s) of thesetethers will experience a relatively greater displacement duringdeflection of the divider, thereby permitting the vent cap(s) 60 a and60 b attached to the tethers to open a relatively greater amount andproviding a relatively greater area for region Y. This enables arelatively greater gas flowrate through the vent(s). Similarly, if oneor more the tethers are attached to the divider 100 relatively fartherfrom the region C, the relatively smaller displacement of the outlyingportions of the divider will permit the vent cap(s) 60 a and 60 battached to the tethers to open only a relatively smaller amount,thereby providing a relatively smaller area for region Y and permittinga relatively lower gas flowrate through the vent(s). In a particularembodiment, tethers 70 a and 70 b are attached to the divider 100 at theregion of maximum deflection C.

In addition, the amount of material forming the divider 100 may beadjusted to some degree to correspondingly adjust the maximum amount ordistance the region C deflects in either direction (toward the lowerchamber 104 or toward the upper chamber 102). Referring to FIG. 2A, ifthe divider 100 is formed using a relatively smaller amount or length Lof material (where the dimension L is measured when the divider is laidflat on a flat surface), the region C will deflect a relatively smalleramount in response to an applied pressure to either side of the divider.If the divider 100 is formed using a relatively larger amount or lengthL of material, the divider region C will deflect a relatively greateramount into one of the upper chamber or the lower chamber in response toan applied pressure. This method of controlling the relative degree ofthe divider deflection may also be used to correspondingly control theamount which the vent covers 60 a and 60 b open as previously described,with a divider using a relatively larger amount of material (and havinga correspondingly greater deflection) enabling a relatively greateropening area Y (FIG. 3A) to be produced during deflection of the dividerin direction B. One or more of the design parameters described above maybe adjusted as described to control valve actuation, according to therequirements of a particular application. In more particular embodimentsin which the region C lies along a plane M bisecting the airbag anddivider, each of divider attachment locations 70 a 1 and 70 b 1 ispositioned within a range extending 60 millimeters inclusive along thedivider to either side of plane M. That is, the dimension D1 as seen inFIG. 2A extends up to 60 mm to each side of plane M. It has been foundthat positioning of the tether attachment locations within this range oflocations is especially effective and reliable in securing the ventcovers 60 a and 60 b in a closed condition when the divider is fullydeflected toward lower chamber 104, and also in enabling the vent coversto be rapidly and fully opened when the divider is fully deflectedtoward upper chamber 102.

Referring to FIG. 5, during a second phase of airbag deployment,pressurized gases continue to be transferred from the upper chamber 102into the lower chamber 104, until pressure equilibrium between the upperand lower chambers is reached. This pressure equilibrium may be reachedjust before contact of the torso of the vehicle occupant 800 with theairbag, or the gas may continue to flow into the lower chamber at leastuntil contact with the occupant. Initially, the occupant contacts theairbag in a region exterior of the lower chamber 104. While the divider100 is fully deflected in direction “A” toward the lower chamber 104,tension in the tether members 70 a and 70 b maintains closure of thevent covers as shown in FIG. 2A. When pressure equilibrium is reached,the divider 100 may be substantially planar or otherwise have nopronounced deflection toward either upper chamber 102 or lower chamber104. Thus, the tension in tethers 70 a and 70 b maintaining vent covers60 a and 60 b in the closed condition may be relaxed to some degreeimmediately prior to contact of the vehicle occupant with the airbag.

In addition, impact by the occupant torso begins to increase thepressure in the lower chamber (i.e., the contact begins to reverse theprevious pressure differential between the upper and lower chambers,causing the deflection in direction “A” to diminish responsive tooccupant impact with the airbag).

Referring to FIGS. 2B and 2C, during a third phase of phase of airbagdeployment, impact by the occupant torso begins to increase the pressurein the lower chamber (i.e., the contact begins to reverse the previouspressure differential between the upper and lower chambers, causing thedeflection in direction “A” to diminish responsive to occupant impactwith the airbag). As the torso of the occupant 800 continues to press onthe airbag exterior outside lower chamber 104, the pressure in the lowerchamber increases to where the lower chamber pressure exceeds the upperchamber pressure. This shift reverses the direction of dividerdeflection, from direction “A” to direction “B”, wherein the divider isdeflected toward upper chamber 102. The relatively higher pressure inthe lower chamber 104 also causes flow-restricting valve mechanism 113to close or otherwise actuate so as to restrict gas flow from the lowerchamber 104 back into the upper chamber 102, thereby maintaining theelevated pressure in lower chamber 104. As the divider deflects indirection “B”, the tension in tether members 70 a and 70 b (which wasmaintaining closure of the vent covers) is reduced. This reduced tensionallows the vent covers 60 a and 60 b to open, thereby permitting releaseof pressurized gas from the upper chamber via openings 210 and 212responsive to contact of the vehicle occupant's head with the portion ofthe airbag exterior of upper chamber 102, and softening or reducing thecontact forces between the bag and the passenger's head. Stated anotherway, contact between the passenger's torso and the airbag exterior ofthe lower chamber 104 acts to increase pressure in the lower chamber andproduce deflection of the divider toward the upper chamber 102. Thisdeflection moves the anchor locations 70 a 1 and 70 b 1 of the tetherstoward the vents 210 and 212, thereby permitting the lid members 60 aand 60 b to open and gases to exit the upper chamber 102 through thevents responsive to contact of the passenger's head with the airbagexterior of the upper chamber 102. Thus, when the vehicle occupant'shead contacts the airbag exterior of the upper chamber, the contactbetween the passenger's head and the airbag is softened.

In a particular embodiment, the airbag is structured such that theoccupant's torso makes contact with the airbag exterior of the lowerchamber before the occupant's head makes contact with the airbagexterior of the upper chamber. For example, the airbag may be structuredsuch that the portion of the bag exterior of the lower chamber 104extends outwardly toward the occupant's torso when inflated, so that asthe torso pivots and moves forward during a collision event, the lowerportion of the torso contacts the airbag. This increases the pressure inlower chamber 104, thereby deflecting the divider toward the upperchamber and actuating the valve 113 to restrict backflow into the upperchamber 102 as previously described. Thus, in this embodiment, prior tocontact of the occupant's head with the airbag, the divider is fullydeflected toward the upper chamber due to pressure exerted on the lowerchamber by the torso.

In particular embodiments, holes 210 and 212 are circular and havediameters in the range 20-75 millimeters inclusive. In a particularembodiment, the holes 210 and 212 have diameters of 40 millimeters.However, the vent hole dimensions necessary to provide a desired airbagperformance for a particular application may be determined analyticallyor iteratively, through experimentation, using known methods.

In particular embodiments, the characteristics of features such as theoptimum lengths of tethers 70 a and 70 b, the optimum locations alongdivider 100 at which the tethers may be attached, the optimum dividerlength L, the optimum sizes of vent holes 210 and 212, and otherpertinent parameters may be specified so that the flowrate of gasesexiting one of openings 210 and 212 is different from the flowrate ofgases exiting the other one of openings 210 and 212. This enables thedeflation rates of different portions of upper chamber 102 to beadjusted or tuned to meet particular performance requirements.

Features such as the optimum lengths of tethers 70 a and 70 b, theoptimum locations along divider 100 at which the tethers may beattached, the optimum divider length L, the optimum sizes of vent holes210 and 212, and other pertinent parameters may be determinedanalytically or iteratively, through experimentation for a givenapplication using known methods.

Referring again to FIG. 1, in addition to openings 210 and 212 which areclosable by lid members 60 a and 60 b, one or more optional pressurerelief openings 802 and 804 may also be provided along each of arespective one of side panels 14 and 16. Openings 802 and 804 areconfigured and located on the airbag so as to be always in an opencondition. While holes 210 and 212 are only opened responsive to contactbetween the airbag and a passenger, holes 802 and 804 serve as pressurerelief openings to prevent excessive internal airbag pressures fromdeveloping if lid members 60 a and 60 b are not actuated to releasegases from openings 210 and 212 in time to prevent an undesirableinternal airbag pressure. In particular embodiments, holes 802 and 804are circular and have diameters in the range 30-75 millimetersinclusive. In a particular embodiment, the holes 802 and 804 havediameters of 60 millimeters. However, the pressure relief holedimensions necessary to provide a desired airbag performance for aparticular application may be analytically or iteratively, throughexperimentation, using known methods.

In particular embodiments described herein, the inflated shapes of theairbag 10 and the divider 100 and the positions of the intersectionsbetween divider 100 and the interior portions of the panels 12, 14, 16to which the divider embodiments are attached are configured so as toensure that the head and neck regions (collectively designated 302 for aHybrid III 5th percentile female test ATD 305, 402 for Hybrid III 50thpercentile male test ATD 405, and 502 for a Hybrid III 95th percentilemale test ATD 505, as shown in FIG. 6A) of passengers of various sizesimpact the bag along the exterior of the upper chamber 102 of the bag(i.e., that the upper chamber 102 absorbs the impact of the head andneck regions of the passenger). The configuration of the divider, itspositioning within the airbag, and the position of a seam 201 attachingthe divider leading edge to the panel 12 enable the cushion to match theforward movement of the relatively heavier thoracic regions (generallydesignated 304 in ATD 305, 404 in ATD 405, and 504 in ATD 505) to theforward movement of the relatively smaller and lighter head & neckregions 302, 402, 502.

Referring to FIG. 6A, in the embodiment shown in FIGS. 7-9D, the dividerleading edge is attached to the main panel along a seam 201 positionedso as to reside within a zone Z defined at a lower end Z2 by the hippivot 202 of a seated Hybrid III 5th female ATD 305, and at an upper endZ1 by the shoulder pivot 206 of a seated Hybrid III 50th ATD 405,inclusive. These boundary positions and other characteristics of all thetest ATD's described herein are specified in 49 CFR Part 572, which isincorporated herein by reference in its entirety, and which may befound, for example, athttp://www.gpo.gov/fdsys/pkg/CFR-2011-title49-vol7/pdf/CFR-2011-title49-vol7-part572.pdf,or at http://www.law.cornell.edu/cfr/text/49/part-572. In a particularembodiment, the hip pivot 202 of the seated Hybrid III 5th female ATDresides at a vertical distance of 3.30 inches above the portion of theseat in contact with the ATD, and the shoulder pivot 206 of the seatedHybrid III 50th male ATD resides at a distance of 17.5 inches above theportion of the seat in contact with the ATD. Thus, the dimension of thezone Z is 14.2 inches.

It is noted that the hip pivots of the seated ATD's 305, 405, and 505are collinear or at the same level, so that the hip pivot of the seatedHybrid III 50th male ATD 405 may be referred to as 202′. This commonboundary of the zone Z may also serve as a reference axis. Also, in thisembodiment, the portions of the body located above the respectiveshoulder pivots on ATD's 305, 405 and 505 are considered to define therespective head and neck regions of the ATD's.

In embodiments described herein, the various airbag elements are shapedand connected to each other so that, when fully inflated, the front side20 of the bag aids in maintaining alignment of the head, neck, andthoracic body regions along a line L as shown in FIG. 6B during impactwith the airbag and after contact with the bag. It is desirable tomaintain this alignment during and after contact with the bag, so thatthe entire upper body of the passenger (i.e., the head, neck, andthoracic regions) effectively pivots about the hip axis of thepassenger, as shown in FIG. 6B. To this end, as seen in FIG. 6B, the bagis structured such that the portions of the inflated bag front side 20contacted by the passenger form an essentially flat plane, indicated bythe plane P in the drawing. It is also desirable that the line L alongwhich these body regions lie be parallel with the plane P during andafter impact with the airbag, to aid in preventing differential motionof the head/neck region and the thorax region (i.e., a bending of theneck and head regions relative to the thorax).

Referring now to FIGS. 7-9D, in particular embodiments, the location ofdivider opening 112 a (and the locations of all other openings, ifmultiple divider openings are employed) may be determined in a mannersimilar to that set forth in U.S. application Ser. No. 14/212,701, filedon Mar. 14, 2014, the disclosure of which is hereby incorporated byreference in its entirety.

Referring to the embodiment shown in FIGS. 7-9D, it has been found thatairbag performance after activation and during filling is affected bythe horizontal distance D10 taken between a vertical plane P10 extendingthrough the seam 205 (where the divider 100 is attached to the mainpanel 12 adjacent the airbag mouth 22 a) when the airbag is deployed ina vehicle in a fully inflated state, and the location(s) of any edge(s)of opening 112 a closest to the plane P10 when the airbag is in theinflated state. The distance D10 may be taken as the shortest distancebetween plane P10 and a vertical plane P9 passing through the closestedge(s) of opening 112 a (or through the closest edge of any opening ifmultiple openings are used) when the airbag is in the inflated state.

More specifically, if any edges of any divider openings are locatedcloser to the plane P10 than a predetermined distance 1000 f (as definedby a vertical plane P15) from plane P10, the movements of the componentsof valve mechanisms controlling gas flow through the divider openingsmay be constricted by proximity to the vehicle instrument panel profile,thereby impairing valve operation.

Airbag performance after activation and during filling is also affectedby the distance D11 between a vertical plane P12 passing through a seam201 (along which divider 100 is attached to occupant contact face 20 ofthe airbag) when the airbag is in a fully inflated state (as shown inFIG. 7), and the location(s) of any edge(s) of divider opening 112 a (orany other divider opening(s)) closest to the plane P12 when the airbagis in the inflated state. The distance D11 may be taken as the shortestdistance between plane P12 and a vertical plane P11 passing through theclosest edge of any divider opening when the airbag is in the inflatedstate. More specifically, if any edges of any divider openings arelocated nearer to the occupant contact side 20 of the cushion than apredetermined distance 1000 j (defined by a vertical plane P14) from theoccupant contact side (as measured from the plane P12, the airbag willhave a tendency to pull excessively downward during inflation of theupper chamber 102, thereby pulling the airbag out of the desiredalignment with the passenger's body prior to contact between thepassenger and the inflating airbag.

Thus, at locations along the divider between planes P14 and P15 is aninterval or zone in which the divider openings 112 a (or openings)should be positioned to achieve sufficient gas flow to rapidly filllower chamber 104 without having the upper chamber pressure becoming toohigh to meet the NHTSA airbag performance requirements for anout-of-position 3 year old or 6 year old child, evaluated for position-1(as shown in FIGS. 9A-9D). By positioning the opening(s) and associatedvalve mechanism(s) within the range defined by locations 1000 j and 1000f, the force exerted by the inflated airbag on position 3 & 6 year oldsin position-1 will be equally divided between the child's head andthorax regions.

While movement of the edge(s) of the divider openings past the distance1000 j farther away from the front portion of the main panel 12mitigates excessive downward pull of the airbag during the initialstages of inflation, thereby improving the overall performance of thebag with respect to an adult occupant, this positioning of theopening(s) may result in less-than-optimum performance for Out ofPosition-1 children. There is a balance between these requirements whichmay be tuned for a specific vehicle or specific application in order toachieve the best overall performance both early and later in thedeployment event, and for both types of passenger. Between planes P14and P15 lie optimal locations for the divider openings, to tune theinitial cushion fill and cushion pitch to achieve the desired resultsfor a given application. The exact desired location of the divideropening (or openings) for a particular application may be determinediteratively, by experimentation, or analytically.

In particular embodiments of the airbag, it is desired to position thedivider opening(s) along the divider 100 so that, during inflation, theairbag reacts with a child passenger in a predetermined manner. Morespecifically, the divider are positioned along the divider such that, asthe upper chamber 102 fills in the initial stage of deployment, the bagupper chamber 102 inflates above the top of the head 700 a of a HybridIII 3 and 6-Year Old Anthropomorphic Test Device (ATD) (generallydesignated 700) when the head is positioned resting against or proximatethe vehicle instrument panel 213 at a location specified as Position-2for Out of Position (OOP) testing in accordance with FMVSS Standard No.208 (which may be found, for example, athttp://www.law.cornell.edu/cfr/text/49/571.208), which is incorporatedherein by reference in its entirety. The Hybrid III 3 and 6-Year Oldtest ATD has physical parameters defined by 49 CFR Part 572 (which maybe found at http://www.law.cornell.edu/cfr/text/49/part-572), 49 CFRPart 572, Subpart I (which may be found athttp://www.law.cornell.edu/cfr/text/49/part-572/subpart-I), and 49 CFRPart 572, Subpart C (which may be found athttp://www.law.cornell.edu/cfr/text/49/part-572/subpart-C), all of whichare which is incorporated herein by reference in their entireties.Position-1 and Position-2 for Out of Position testing are schematicallyillustrated in FIGS. 9A-9D (Position 1) and FIGS. 8A-8B (Position 2),and described in sections 22.4.2 and 22.4.3 of FMVSS208, respectively,the descriptions of which are herein incorporated by reference.

As gases flow into the lower chamber 104 from the upper chamber 102, thelower chamber 104 inflates in the later stages of deployment so as tooccupy a space behind and around the child's head, thereby preventingand/or mitigating harmful interactions between the airbag and thechild's head. This inflation progression is shown in FIGS. 8A and 8B.

The values of D10, D11, 1000 f, 1000 j and other divider openingpositioning parameters are determined as a function of the vehicleinterior dimensions and the placement of the out-of-position-2 child,according to the previously-mentioned FMVSS208 standards. Practicallimitations of the divider opening placement affect the airbagperformance for an out-of-position 3-year old or 6-year old child, asdefined by FMVSS Standard No. 208. By positioning the divider opening(s)within the range defined by locations P14 and P15 (i.e., zone Z3) inFIGS. 8A and 8B, the forces exerted by the airbag on both the 3-year oldand 6-year old child in Position-1 (shown in FIG. 9A) will bedistributed between the child's head and thorax regions. For example, ithas been found that when the divider openings are positioned within adistance 1000 j from a seam connecting the divider 1000 with theoccupant side of the airbag, the airbag will tend to impact the childwhen deployed, before completely filling. This contact with the childtends to prevent the gases from flowing into the lower chamber, whichmay produce greater forces acting on the child. See FIG. 9B thatillustrates this configuration, for example. Also, it has been foundthat when the divider openings are positioned within a predetermineddistance 1000 f along the divider from an inflator side 22 of the airbagtoward an occupant side of the airbag, the airbag will tend to impactthe child when deployed, before completely filling, with the resultspreviously mentioned. In contrast, referring to FIGS. 9C and 9D, it hasbeen found that when the divider opening(s) are positioned within zoneZ3 as previously described, the gases are permitted to flow into thelower chamber without obstruction. This creates a more evenlydistributed loading on the child's head and thoracic regions. Also, withthis placement of the divider openings and associated valves, the gasescan more easily flow out of the vent holes 210 and 212 from the upperchamber. As illustrated in FIGS. 8A and 8B, P15 is defined by alignmentwith the out-of position 2 leading edge of the child's head on theinstrument panel 213 (per FMVSS208). P14 is aligned with the shoulderbolt 701 of the ATD. Z3 is of course defined as the region spanningbetween P14 and P15.

Further to FIGS. 9C and 9D, it should be appreciated that thelocation(s) of the divider opening(s) and any associated valvemechanism(s) are preferably positioned within Z3 as defined in thedeployed airbag. Accordingly, it will be appreciated that, as describedin the examples given below, the out-of-position 1 and out-of-position 2FMVSS208 defined above are particularly important in certain embodimentswith regard to placement of the divider openings. It has unexpectedlybeen found that placement of all the divider openings within zone 3 orZ3 as defined herein and with reference to a deployed airbag shown inFIG. 9D for example, contributes to effectively managing and mitigatingthe forces acting on an out-of-position child for example, as indicatedin 3-year old and 6-year old HAI ATD testing under FMVSS208. It will beappreciated that although at least one or more openings 112 a should bepositioned within Z3 to ensure fluid communication between the upper andlower airbag chambers with regard to airbag contact with anout-of-position child as shown in FIG. 9A (position 1 of FMVSS208), oneor more divider openings may also be positioned outside of Z3 dependingon other design criteria.

Stated another way, it has been found that an optimum inflation profilerange and alignment with the passenger's body as shown in FIG. 6B, aswell as the bag inflation progression shown in FIGS. 8A and 8B, can beachieved by positioning all divider openings such that all edges of allthe openings reside within the zone Z3 bounded by planes P14 and P15 asdefined herein, which may also be defined on one side by a verticalplane P15 shown in FIG. 8A corresponding to a location abutting thefront-most portion of the head of the Hybrid III 6-Year OldAnthropomorphic Test Device when the head of the Hybrid III 6-year oldis in Position-2 for FMVSS208 Out of Position testing as specifiedabove, and on an opposite side by a vertical plane P14 (see FIG. 8A) asdefined herein. As known in the pertinent art, an anthropomorphic testdevice is a human form in shape, mass and mechanical response, equippedwith sensors including accelerometers, deflection sensors and othermeasurement devices, to simulate the performance of the human body. Itis used in the assessment of injury potential in vehicle safety testing.In one embodiment, plane P14 is spaced apart approximately 7 inches fromplane P15 toward a rear of the vehicle when the airbag is inflated. Thiseffectively positions the divider opening(s) within a zone enclosing thehead of the Hybrid III 6-Year Old ATD as the airbag inflates over thehead of ATD as shown in FIG. 8B. The distance between planes P15 and P14defines a zone Z3 in which the opening 112 a may be positioned.

In particular embodiments, the tether attachment locations 70 a 1 and 70b 1 previously described are also positioned within the zone Z3. Thisfacilitates the desired airbag response with respect to children inFMVSS208 Positions 1 and 2 as previously described.

It has also been found that a total area of the divider opening 112 a(or openings) within a range of 700 square millimeters (achievableusing, for example, one opening of approximately 15 mm radius) to 32,000square millimeters (achievable using, for example, one opening ofapproximately 100 mm radius opening) is desirable for helping to ensurethat airbag performance is within an optimum range. In embodiments ofthe present invention, which use a directional valve mechanism tofacilitate inflow and restrict backflow from the lower chamber to theupper chamber as previously described, the total areas of the divideropenings may need to be at or near an upper end of this range of openingsizes 700 to 32,000 square millimeters, to provide the necessaryinflation profile given the reduction in flow caused by turbulence andfriction in the gases as they flow through the opening(s) and interactwith the portions of the valve.

In one embodiment, the opening 112 a (or openings) are circular.However, the opening(s) can have any desired shape, as long as the totalarea of the opening(s) is within the range specified above, and as longas all of the opening edges are positioned within the zone definedabove.

In addition, the number of divider openings and the optimum size(s) ofthe opening(s) formed in divider 100 for a particular application may bedetermined based on the type of vehicle collision pulse and interiorgeometry of the vehicle in which the airbag is installed, the desiredfill rate of the airbag, the volume ratio, the type of directional valveused, the overall dimensions and curvature of the instrument panel 213,and other pertinent factors. The size(s) and position(s) of the divideropening(s) as described herein facilitate smooth and rapid transfer ofinflation gases from the upper chamber to the lower chamber duringinitial stages of airbag filling. Once equilibrium is substantiallyreached between the upper and lower chamber pressures, flow from onechamber to the other is reduced. As the occupant begins to load thelower chamber of the cushion, the pressure within the lower chamberincreases, causing the operating member of the valve to restrict thebackflow of gas from the lower chamber to the upper chamber. Thisrestricted flow now is effectively absorbing energy from the occupantinteraction with the bag lower chamber. The flow restriction can also beadjusted or tuned in order to absorb the occupant energy as required fora particular application. Each of the directional valves (not shown)controlling flow from the upper chamber to the lower chamber can have asingle operating member which provides both a desired inflow (to thelower chamber) and a desired backflow (back from the lower chamber)characteristic, or the valve can have one operating member forcontrolling inflow to the lower chamber and another operating member tocontrol backflow from the lower chamber. In the later phases of theoccupant loading of the cushion, backflow from the lower chamber may gointo the upper chamber, from where it is discharged into the environmentthrough the vent holes 210 and 212 located in the wall of the upperchamber.

In the case of an Out of Position child in accordance with the FMVSS208Position-2 testing standard, the initial stages of the cushiondeployment development remain the same as described above. However, thegas flow from the upper chamber into the lower chamber as regulated bythe divider valve mechanism may be different when a child interacts withthe cushion. In the case of the Out of Position-2 child, the volume ofthe lower chamber is decreased due to the space occupied by the Out ofPosition Child. The divider valve mechanism continues to permit the flowof gases from the upper chamber into the lower chamber. However, thevalve mechanism may also allow the gas to continue to flow into thelower chamber until the cushion's lower chamber and upper chamberinternal pressures are in equilibrium, thereby stabilizing theinteraction between the cushion and the out of position child. Thedivider structure and attachment to the airbag outer shell panels, thedivider valve mechanism(s) and the airbag main vent designs may bestructured to facilitate rapid transition of this state of equilibriuminto an adaptive state, wherein the cushion changes from a state of gasflow into the lower chamber to a state where the gas flow is increasedout of the main vents (located in wall(s) of the upper chamber) into theenvironment. This increased flow out of the cushion allows for decreasedpressure within the upper chamber and then allows for the backflow ofgases from the lower chamber back into the upper chamber and out of thevent openings 210 and 212 into the environment. This adaptability of thevalve mechanisms to regulate the flow communication between the twochambers is important for the protection of adult and child occupants.

An airbag and an occupant protection system for an automotive vehiclecontaining the airbag, wherein the airbag is made in accordance with themethod given above, are also contemplated in accordance with the presentinvention. The passenger side airbag for each unique vehicle maytherefore be designed by iteratively reconciling the requirements ofFMVSS208 with the present airbag design for each vehicle.

Referring now to FIG. 10, any of the airbag embodiments described hereinmay be incorporated into an airbag system 200. Airbag system 200includes at least one airbag 10 in accordance with an embodimentdescribed herein and a gas source 915 incorporated into or operativelycoupled to airbag 10 so as to enable fluid communication with aninterior of the airbag. Airbag 10 may be mounted in a vehicle dashboard211 or another suitable portion of the vehicle. Airbag system 200 mayalso be in communication with a crash event sensor 210 operating inassociation with a known crash sensor algorithm that signals actuationof airbag system 200 in the event of a collision.

Referring again to FIG. 10, an airbag in accordance with an embodimentdescribed herein or an airbag system 200 including such an embodimentmay also be incorporated into a broader, more comprehensive vehicleoccupant protection system 180 including additional elements such as asafety belt assembly 150. FIG. 10 shows a schematic diagram of oneexemplary embodiment of such a protection system. Safety belt assembly150 includes a safety belt housing 152 and a safety belt 160 extendingfrom housing 152. A safety belt retractor mechanism 154 (for example, aspring-loaded mechanism) may be coupled to an end portion of the belt.In addition, a safety belt pretensioner 156 may be coupled to beltretractor mechanism 154 to actuate the retractor mechanism in the eventof a collision. Typical seat belt retractor mechanisms which may be usedin conjunction with the safety belt embodiments of the present inventionare described in U.S. Pat. Nos. 5,743,480, 5,553,803, 5,667,161,5,451,008, 4,558,832 and 4,597,546, incorporated herein by reference.Illustrative examples of suitable pretensioners are described in U.S.Pat. Nos. 6,505,790 and 6,419,177, incorporated herein by reference.

Safety belt system 150 may also be in communication with a crash eventsensor 158 (for example, an inertia sensor or an accelerometer)operating in association with a known crash sensor algorithm thatsignals actuation of belt pretensioner 156 via, for example, activationof a pyrotechnic igniter (not shown) incorporated into the pretensioner.U.S. Pat. Nos. 6,505,790 and 6,419,177, which are incorporated herein byreference, provide illustrative examples of pretensioners actuated insuch a manner.

It is important to note that the construction and arrangement of theairbag, valve, and tether embodiments as shown and described herein areillustrative only. Although only a few embodiments have been describedin detail in this disclosure, those skilled in the art who review thisdisclosure will readily appreciate that many modifications are possible(e.g., variations in sizes, dimensions, structures, shapes andproportions of the various elements, values of parameters, mountingarrangements, use of materials, colors, orientations, etc.) withoutmaterially departing from the novel teachings and advantages of thesubject matter disclosure herein. For example, elements shown asintegrally formed may be constructed of multiple parts or elements, theposition of elements may be reversed or otherwise varied, and the natureor number of discrete elements or positions may be altered or varied.Accordingly, all such modifications are intended to be included withinthe scope of the present application. The order or sequence of anyprocess or method steps may be varied or re-sequenced according toalternative embodiments. Other substitutions, modifications, changes andomissions may be made in the design, operating conditions andarrangement of the exemplary embodiments.

In addition, airbags having the same exterior dimensions and structuremay be used for multiple applications, because variations in airbagperformance characteristics due to design requirements may be achievedby modifying the interior structure of the airbag (for example, bychanging the location of the divider, by modifying the flowcharacteristics of the various valve embodiments connecting the upperand lower chambers, and by changing the upper chamber vent locations andcharacteristics). This ability to use a common exterior structureprovides a degree of uniformity in bag design and manufacturing.

It will be understood that the foregoing descriptions of the variousembodiments are for illustrative purposes only. As such, the variousstructural and operational features herein disclosed are susceptible toa number of modifications, none of which departs from the scope of theappended claims.

What is claimed is:
 1. An airbag comprising: an outer shell defining aninterior; at least one vent opening structured to enable fluidcommunication between the interior and an exterior of the airbag; adivider dividing the airbag interior into an upper chamber and a lowerchamber separate from, and in fluid communication with, the upperchamber; and a vent cover for covering said vent opening, said ventcover operatively coupled to the at least one vent opening and to thedivider wherein said vent cover is opened based on a predeterminedposition of the divider.
 2. The airbag of claim 1 wherein the lowerchamber is structured to cushion the torso, but not the head, of avehicle occupant.
 3. The airbag of claim 1 further comprising aninter-chamber venting system operatively coupled to the divider, theventing system being structured to permit gas to flow unobstructed fromthe upper chamber through the divider into the lower chamber, theventing system being structured to restrict gas backflow from the lowerchamber into the upper chamber.
 4. The airbag of claim 3 wherein theventing system is structured to close so as to restrict backflow fromthe lower chamber into the upper chamber responsive to pressure exertedon the airbag by a torso of the occupant prior to contact between theairbag and a head of the occupant.
 5. The airbag of claim 1 wherein thedivider is structured to open the vent cover when a pressure in thelower chamber is greater than a pressure in the upper chamber.
 6. Theairbag of claim 1 further comprising a tether operatively connecting thedivider to the vent cover such that deflection of the divider in a firstdirection acts to pulls the vent cover into a closed condition, therebyrestricting flow of gas through the at least one vent opening.
 7. Theairbag of claim 6 wherein the tether operatively connects the divider tothe vent cover such that deflection of the divider in a second directionenables the valve cover to open responsive to gas pressure within theupper chamber, so as to permit an unobstructed flow of gas through theat least one vent opening.
 8. A vehicle occupant protection systemcomprising an airbag in accordance with claim
 1. 9. An airbag systemcomprising an airbag in accordance with claim
 1. 10. A vehicle includingan airbag in accordance with claim
 1. 11. An airbag comprising: an outershell defining an interior; at least one vent opening structured toenable fluid communication between the interior and an exterior of theairbag; a divider dividing the airbag interior into a first chamber anda second chamber separate from, and in fluid communication with, thefirst chamber; a vent cover closable over the at least one vent openingso as to restrict a flow of gas through the at least one vent opening,the vent cover also being openable so as to permit an unobstructed flowof gas through the at least one vent opening wherein said vent cover isopened based on a predetermined deflection of the divider; and a tetheroperatively connecting the vent cover to the divider such that the ventcover is closed when the divider is deflected toward the second chamber,and such that the vent cover is open when the divider is deflectedtoward the first chamber.
 12. The airbag of claim 11 further comprising:an inter-chamber venting system operatively coupled to the divider, theventing system being openable to permit gas to flow unobstructed fromthe first chamber through the divider into the second chamber, when apressure in the first chamber is greater than a pressure in the secondchamber, the venting system being closable to restrict gas backflow fromthe second chamber into the first-chamber when the pressure in thesecond chamber is greater than a pressure in the first chamber.
 13. Avehicle occupant protection system comprising an airbag in accordancewith claim
 11. 14. An airbag system comprising an airbag in accordancewith claim
 11. 15. A vehicle including an airbag in accordance withclaim
 11. 16. An airbag comprising: an outer shell defining an interior;a divider dividing the interior into an upper chamber and a lowerchamber separate from, and in fluid communication with, the upperchamber, the divider being deflectable toward the lower chamber and alsotoward the upper chamber; at least one vent opening structured to enablefluid communication between the interior and an exterior of the airbag;and a vent cover closable over the at least one vent opening so as torestrict a flow of gas through the at least one vent opening, the ventcover also being openable so as to permit an unobstructed flow of gasthrough the at least one vent opening wherein said vent cover is openedbased on a predetermined deflection of the divider, wherein the divideris structured to deflect in a direction toward the first chamberresponsive to pressure exerted on the airbag exterior by contact with atorso of a vehicle occupant, prior to contact between a head of theoccupant and the airbag.
 17. A vehicle occupant protection systemcomprising an airbag in accordance with claim
 16. 18. An airbag systemcomprising an airbag in accordance with claim
 16. 19. A vehicleincluding an airbag in accordance with claim
 16. 20. The airbag of claim16 wherein said vent cover is closable to restrict a flow of gas throughthe at least one vent opening when the divider is deflected in a firstdirection, and openable so as to permit an unobstructed flow of gasthrough the at least one vent opening, the vent cover being operativelycoupled to the divider such that the vent cover is openable when thedivider is deflected in a direction toward the first chamber and closedwhen the divider is deflected toward the second chamber.